Aerofoils are used within turbine engines and are subjected to high temperatures such that adequate cooling is required to maintain their operability. Typically, cooling channels are provided through the aerofoil in which coolant, normally air, flows in order to cool the airflow. Unfortunately, these internal cooling channels are prone to blockage by dirt or other contaminants.
Previous approaches to avoiding coolant channel blockage have included channel oversizing, over specifying the number of cooling channels required and incorporation of dirt separation or filtration devices. These approaches inherently result in significant efficiency penalties along with additional fabrication and manufacturing costs.